IB/mlx5: Add support for don't trap rules

Each bypass flow steering priority will be split into two priorities:
1. Priority for don't trap rules.
2. Priority for normal rules.

When user creates a flow using IB_FLOW_ATTR_FLAGS_DONT_TRAP flag, the
driver creates two flow rules, one used for receiving the traffic and
the other one for forwarding the packet to continue matching in lower
or equal priorities.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 03c418c..5863644 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -1369,11 +1369,20 @@
 	return 0;
 }
 
+static int ib_prio_to_core_prio(unsigned int priority, bool dont_trap)
+{
+	priority *= 2;
+	if (!dont_trap)
+		priority++;
+	return priority;
+}
+
 #define MLX5_FS_MAX_TYPES	 10
 #define MLX5_FS_MAX_ENTRIES	 32000UL
 static struct mlx5_ib_flow_prio *get_flow_table(struct mlx5_ib_dev *dev,
 						struct ib_flow_attr *flow_attr)
 {
+	bool dont_trap = flow_attr->flags & IB_FLOW_ATTR_FLAGS_DONT_TRAP;
 	struct mlx5_flow_namespace *ns = NULL;
 	struct mlx5_ib_flow_prio *prio;
 	struct mlx5_flow_table *ft;
@@ -1383,10 +1392,12 @@
 	int err = 0;
 
 	if (flow_attr->type == IB_FLOW_ATTR_NORMAL) {
-		if (flow_is_multicast_only(flow_attr))
+		if (flow_is_multicast_only(flow_attr) &&
+		    !dont_trap)
 			priority = MLX5_IB_FLOW_MCAST_PRIO;
 		else
-			priority = flow_attr->priority;
+			priority = ib_prio_to_core_prio(flow_attr->priority,
+							dont_trap);
 		ns = mlx5_get_flow_namespace(dev->mdev,
 					     MLX5_FLOW_NAMESPACE_BYPASS);
 		num_entries = MLX5_FS_MAX_ENTRIES;
@@ -1434,6 +1445,7 @@
 	unsigned int spec_index;
 	u32 *match_c;
 	u32 *match_v;
+	u32 action;
 	int err = 0;
 
 	if (!is_valid_attr(flow_attr))
@@ -1459,9 +1471,11 @@
 
 	/* Outer header support only */
 	match_criteria_enable = (!outer_header_zero(match_c)) << 0;
+	action = dst ? MLX5_FLOW_CONTEXT_ACTION_FWD_DEST :
+		MLX5_FLOW_CONTEXT_ACTION_FWD_NEXT_PRIO;
 	handler->rule = mlx5_add_flow_rule(ft, match_criteria_enable,
 					   match_c, match_v,
-					   MLX5_FLOW_CONTEXT_ACTION_FWD_DEST,
+					   action,
 					   MLX5_FS_DEFAULT_FLOW_TAG,
 					   dst);
 
@@ -1481,6 +1495,29 @@
 	return err ? ERR_PTR(err) : handler;
 }
 
+static struct mlx5_ib_flow_handler *create_dont_trap_rule(struct mlx5_ib_dev *dev,
+							  struct mlx5_ib_flow_prio *ft_prio,
+							  struct ib_flow_attr *flow_attr,
+							  struct mlx5_flow_destination *dst)
+{
+	struct mlx5_ib_flow_handler *handler_dst = NULL;
+	struct mlx5_ib_flow_handler *handler = NULL;
+
+	handler = create_flow_rule(dev, ft_prio, flow_attr, NULL);
+	if (!IS_ERR(handler)) {
+		handler_dst = create_flow_rule(dev, ft_prio,
+					       flow_attr, dst);
+		if (IS_ERR(handler_dst)) {
+			mlx5_del_flow_rule(handler->rule);
+			kfree(handler);
+			handler = handler_dst;
+		} else {
+			list_add(&handler_dst->list, &handler->list);
+		}
+	}
+
+	return handler;
+}
 enum {
 	LEFTOVERS_MC,
 	LEFTOVERS_UC,
@@ -1558,7 +1595,7 @@
 
 	if (domain != IB_FLOW_DOMAIN_USER ||
 	    flow_attr->port > MLX5_CAP_GEN(dev->mdev, num_ports) ||
-	    flow_attr->flags)
+	    (flow_attr->flags & ~IB_FLOW_ATTR_FLAGS_DONT_TRAP))
 		return ERR_PTR(-EINVAL);
 
 	dst = kzalloc(sizeof(*dst), GFP_KERNEL);
@@ -1577,8 +1614,13 @@
 	dst->tir_num = to_mqp(qp)->raw_packet_qp.rq.tirn;
 
 	if (flow_attr->type == IB_FLOW_ATTR_NORMAL) {
-		handler = create_flow_rule(dev, ft_prio, flow_attr,
-					   dst);
+		if (flow_attr->flags & IB_FLOW_ATTR_FLAGS_DONT_TRAP)  {
+			handler = create_dont_trap_rule(dev, ft_prio,
+							flow_attr, dst);
+		} else {
+			handler = create_flow_rule(dev, ft_prio, flow_attr,
+						   dst);
+		}
 	} else if (flow_attr->type == IB_FLOW_ATTR_ALL_DEFAULT ||
 		   flow_attr->type == IB_FLOW_ATTR_MC_DEFAULT) {
 		handler = create_leftovers_rule(dev, ft_prio, flow_attr,